Field
The disclosed technology generally relates to a semiconductor device, and more particularly to a gate all around (GAA) semiconductor device and a method of fabricating the same.
Description of the Related Technology
Increasing chip density is the workhorse of the semiconductor industry. Among other trends, one trend in the semiconductor industry is a shift from planar devices to devices utilizing fully-depleted and/or three dimensional architectures, such as FinFET devices. However, as FinFET devices start to face their own challenges associated with scaling to advanced technology nodes, e.g., 10 nm technology node and beyond, including performance challenges arising from parasitic capacitances and resistances and processing challenges arising from advancedpatterning, devices having alternative architectures and structures are being explored. One device being explored is gate-all-around (GAA) nanowire (NW) devices, which are promising candidates for replacing FinFET devices in future technology generations, in part due to their superior electrostatic and gate control. For example, it has been noted that channel lengths can be more aggressively scaled in a GAA NW device compared to FinFET devices. In addition, an undoped channel may be used in a GAA NW device, thereby reducing the threshold voltage variation between devices. Furthermore, to achieve higher layout efficiency and device density, GAA NW devices may be vertically stacked.
Patent application WO2014018201 A1 describes a nanowire transistor device and a method for manufacturing such a nanowire transistor device. The manufacturing technique is based on the so-called top down approach which involves nanowire fabrication using a CMOS compatible technology, such as lithography-based patterning and etching. The CMOS integration scheme in WO2014018201 uses two distinct stacks for nFET and for pFET. The p-type layer stack is manufactured completely independent of the process for the n-type layer stack. The nFET stack and the pFET stack are arranged independently aside of one another.
Thus, there is a need to provide a more compact GAA NW device.